Soft plastic, such as silicone or a thermoplastic elastomer can be used to make a petal valve. Traditionally, to make such a valve, the soft valve body is molded and then ejected from a molding tool. Then, the molded material is punched or sliced to form an X-opening. Forming the X-opening after the molding process adds an extra step to the process of making a petal valve and accordingly adds to the cost of making such a valve.
Previously, it has not been practical to form the X-opening in the valve body during the molding process of the valve body because openings formed by a tool during the molding process would likely be too large to permit effective sealing of the valve. When petal valves or component parts with a petal valve function are made, it is important that the sealing petals or lips can close tightly together after opening without the need for significant compression in the sealing area.
There is thus a continuing, ongoing need for a method of making a petal valve such that the opening of the valve can be made during the molding process and can be made in a open position. Additionally, there is a need for a petal valve with an opening that separates when under fluid pressure and closes to seal the opening against flow when the fluid pressure is relieved.